Base interface for all interfaces that listen for requests from the client browser. All
sub-interfaces of this interface must have a single method which takes no arguments.

New listener interfaces must be registered with Wicket by constructing a
RequestListenerInterface object for the given interface class. The best way to do this is
to create a public static final constant field in your request listener interface. Doing this
will cause the interface to automatically register whenever it is used. For example, see
IRedirectListener.INTERFACE.